Generally, a steer-by-wire system actuates a rack mechanism to steer the vehicle in response to a driver's steering manipulation via electric signals without a steering column.
Test vehicles (used for developing vehicles) having the steer-by-wire system are typically equipped with a failsafe steering device to help ensure the safety of the steer-by-wire system.
If the steer-by-wire system fails to function properly, the steering can be performed safely in the test vehicles via the failsafe steering device.
A mechanical failsafe steering device is conventionally used to transmit the rotational force of a supplement steering wheel to the rack mechanism through a steering shaft.